Football Manager 2013 was cracked by pirates in May of this year, making the game available to illegally download.

Through an in-game anti-piracy tool called 'Home', the development team was able to monitor the IP address of everybody who illegally downloaded the game.

More than 10.1 unique IP addresses were registered, of which 1.8 million played the game more than five times.

The game was illegally downloaded nearly 3.2 million times in China and more than 1 million times in Turkey. At one point, it was even downloaded from inside the Vatican.

During the period of time in which the cracked version was available, activation rates fell by 17%, with calculations suggesting that 1.74% of users would have purchased the game legally if no pirated version was available.

It is believed that if the game was cracked from day-one, the studio would lose $3,700,000 in net revenue.

Deemed the "largest examination of game piracy via peer-to-peer networks to date", the study, which was conducted by three separate universities, claims that over a 90-day period, 173 games were illegally downloaded by 12.6 million people.

The findings contradict a previous study carried out by the ESA, which claimed that 200 games were being illegally downloaded by 10 million people each month.